The present invention relates to a non-contact image reader for reading, recognizing, and checking information, such as document information written on a medium, such as paper, containing printed characters and figures, images, or stamped prints, and inputting the information as image data. The present invention also relates to a document information correction device using the non-contact reader, a control system suited to the device, and a system using the device.
Image input devices, which are commercially available at present, include a flat bed scanner, a sheet scanner, a digital camera, and a camera for paintings and calligraphic works. However, with respect to the currently available flat bed scanner, although the resolution of this device is high, the required installation area is large and the reading speed is low; and, with respect to the currently available sheet scanner, although the required installation area is small, it can read only data on documents in sheet form. With respect to the camera for paintings and calligraphic works, although the resolution thereof is high and some cameras for paintings and calligraphic works can read solids, the device typically is large in scale and the cost thereof is high. As mentioned above, these devices have merits and demerits, and, therefore, they do not completely satisfy the needs of all users.
For purposes of reading documents in a non-contact manner, there are methods, for example, as described in Japanese Patent Application Laid-open 8-9102 (Document 1); Japanese Patent Application Laid-Open 8-274955 (Document 2); Japanese Patent Application Laid-Open 8-154153 (Document 3, Mirror); Japanese Patent Application Laid-Open 8-97975 (Document 4, Book copy); Japanese Patent Application Laid-open 10-13622 (Document 5, White board); and Japanese Patent Application Laid Open 9-275472 (Document 6, Active illumination).
As related references, there are Matsuyama et al., xe2x80x9cEdge detection using multifocus images and distance measurementxe2x80x9d, Electronic Information Communication Society Journal, Vol. J77-D-II, pp. 1048-1058, 1994, (Reference 1); Kodama et al., xe2x80x9cEmphatic acquisition of total focus images using generation of optional focus image generation off-focus images including the parallax from a plurality of images different in focusxe2x80x9d, Electronic Information Communication Society Journal, Vol. J79-D-II, No. 6, pp. 1046-1053, 1996/6, (Reference 2); and Seong Ik CHO, et al, xe2x80x9cShape Recovery of Book Surface Using Two Shade Images Under Perspective Conditionxe2x80x9d, T. IEE JAPAN, Vol. 117-C, No. 10, pp. 1384-1390, 1997 (Reference 3).
The digital camera is superior from the aspect of easily inputting images. However, when the digital camera is used as an image input device for a document, because all information, such as characters, figures, and images, printed on the image plane, such as the surface of a paper, is important, in order to read the information precisely, it is necessary to place the object to be read in an ideal plane state as much as possible and to image the object with the camera precisely positioned opposite the face of the object.
Various proposals for correcting an image which is being read with a camera and which is not positioned precisely opposite to the face of an object being viewed from the front have been made. For example, in Japanese Patent Application Laid-Open 9-289611, there is disclosed a digital camera which is capable of correcting a slant image of an object to produce a pseudo-front image.
However, it is difficult to always keep a medium, such as paper in a flat state, and, actually, the paper is often uneven. When imaging such a paper surface, the conventional flat bed scanner prevents deformation of the image by pressing the paper surface onto a reading surface, such as glass, in order to input the image in a state free of irregularities.
Furthermore, an information correction process for reading a document, referring to a data base for other information, which is not included in the document, and adding the other information to the document, as described in, for example, Japanese Patent Application Laid-open 10-99791, xe2x80x9cMethod for processing change of address of distribution articlexe2x80x9d. In this information correction process, the destination information described on a distribution article is read, the distribution original data base is referred to, and when address change information is registered, the old address is converted to the changed address, and the changed address and name are output to a transfer label. It is described in the patent application that by doing this, the hand work of an operator can be reduced.
However, in the aforementioned conventional examples, it is a premise that a document on an image plane is read almost from above (Documents 1 to 3) and cannot be read from a free position.
A proposal to correct the measuring position by reading a calibration marker (Document 5: white board) has been made. However, a problem arises in that the operation is complicated.
Also, with respect to measurement of the distance to the reading surface from a sensor, the viewing of an observation article sideways (Document 4: book copy), the use of active illumination Document 6: active illumination), and the use of a stereo-camera have been proposed. However, a problem arises in each of these techniques in that the accuracy is bad and the cost is high.
A proposal (References 1 to 3) that the front image is restructured from the obtained distance data has also been made. The simulation by a computer shows that it is necessary to improve the processing speed to make this proposal practicable as an actual product.
When a conventional flat bed scanner is used, the scanning of the reading head takes a lot of time, and when there are many objects to be read, reading requires a lot of time. There is a limit to the reading environment, and the reading position and size are limited. Furthermore, a flat bed scanner is typically large in cross direction, so that installation of the equipment requires a large area.
According to Japanese Patent Application Laid-open 10-99791, the correspondence of postal articles with changed address labels is realized only in a particular sequence, and so a problem arises that, if the sequence of distribution of the articles is broken for any reason, the required correspondence between the articles and the labels cannot be obtained.
An object of the present invention is to provide a non-contact image reader for reading characters written on the surface of a folded form or a thick book in a good operability state and on a high image quality basis.
An another object of the present invention is to provide a non-contact image reader which is simple and has a high degree of freedom.
Still another object of the present invention is to provide a digital camera for use instead of a flat bed scanner and for reading, in this case, even a document or an image which is easily folded, as plane image data.
A further object of the present invention is to provide a document correction device for preventing a mistake in a corresponding relationship when additionally recording a change of address and for returning information on the distribution of an article and performing an effective operation.
To solve the aforementioned problems, the present invention comprises a reading unit for reading images, a reading condition changing unit for changing the reading conditions of the reading unit, a storage unit for storing at least two read images which are read under at least two different reading conditions, and an image correction unit for composing at least two read images and for developing them on a plane.
By reading an image while changing the reading conditions like this, it is possible to analyze the displacement of the image and measure the distance. The image can be developed on a plane from the distance. It is also possible to read not only the upper part of a document, but also to read the other portions at various angles. Therefore, it is possible to read an image on a high image quality basis without pressing a folded form or a thick book. Thus, non-contact image reader having a simple constitution which has a high degree of freedom and is in a good operability state can be provided.
Furthermore, the present invention provides a system comprising a scanner unit including a reading unit for reading images, a reading condition changing unit for changing the reading conditions of the reading unit, a storage unit for storing at least two read images which are read under at least two different reading conditions, and an image correction unit for composing at least two read images and for developing them on a plane; an image processing unit for recognizing an image correction signal output from the scanner unit and for performing image processing; an image display unit for displaying the image-processed data; and an image storage unit for outputting the image-processed data.
By use of such a system, a simple non-contact image reading system requiring a small area on a desk can be provided because not only can an image of high image quality be read in a good operability state, but also the image processing unit, such as a personal computer, and the scanner unit can be connected directly.
Furthermore, to accomplish the above objects, the present invention employs a digital camera including a reading means for digitizing and reading images and a storage means for storing the images read by the reading means, which is characterized in that the digital camera has an image correction means for correcting read images as plane image data when a document is read by the reading means and for outputting the corrected image data. In this case, the digital camera may be structured so that the corrected image data is output to the storage means.
By use of such a device, the reading unit can read images by changing the reading conditions, for example, such as the focus position and swing angle. The image correction means detects characteristic points between images from a plurality of images read under a plurality of different conditions, and, from the diffusion amount of images at that time, the distance between each point of the document and the reading means can be measured. By use of the measured distance, an uneven image can be developed to a plane image. By performing texture mapping necessary to development of an uneven image into a plane image by hardware, a speeding up of the processing can be possible. By integrating and processing distorted images by slant reading in the aforementioned texture mapping process, the conversion count can be reduced, and it can be possible to improve the image quality and increase the processing speed. Furthermore, by changing the filter factor according to the distance and adding and composing images whose diffusion is corrected according to the distance, the white noise caused by photoelectric conversion can be reduced.
The present invention utilizes a digital camera including a reading means for digitizing and reading images and a storage means for storing the images read by the reading means, which is characterized in that the digital camera has an image correction means for correcting read images as plane image data when a document is divided and read by the reading means, a temporary storage means for temporarily storing the corrected image data, and an image combination means for combining a plurality of image data stored in the temporary storage means and outputting them to the storage means.
In such a system, by correcting the images divided and read by the reading unit using the image correction means as plane image data and then combining them using the image combination means, a huge plane image which cannot be fetched by one imaging can be obtained.
When constituting the aforementioned digital camera, the following elements can be added.
(1) The image correction means can be structured so that it detects the distance between each point of the aforementioned document and the reading means from the read results when the reading means changes the focus distance and reads the document several times, and it also divides the read images into polygons and develops the read images in a three-dimensional shape on a plane for each polygon according to the detected distance.
(2) The image correction means can be structured so that when the reading means reads a fixed form of document, it extracts characteristic points of the object from the read image and corrects the distortion generated in the image.
(3) The image correction means can be structured so that it includes a mode for inputting the read image read by the reading means to the storage means as it is and a mode for correcting the read image using the image correction means and inputting it to the storage means, and the two modes can be freely selected.
(4) A characteristic point extraction unit for extracting characteristic points of an object from a read image and a reading range extraction unit for extracting the reading range in the image from the information of extracted characteristic points are provided.
(5) A radio data communication means for performing image data transfer with the outside is provided.
Furthermore, to solve the aforementioned problems, a system for reading the image of a distribution article using a non-contact scanner of a phase-up type and additionally recording information on the distribution article in units of one communication is used. Furthermore, with respect to the additional recording method, not only a method for attaching a label, but also a function is provided wherein, when there is a space for additional recording provided on the surface of a distribution article, information can be directly printed additionally. This additional recording function is selective and a candidate for which method is desirable for the equipment is output according to the read image and an operator can select it.
The starting process for the non-contact scanner is structured so that an operator can simply start the machine operation using a machine switch which is mounted in the same pointer frame as that of the additional recording area change switch and additional recording system selection switch. As a result, misattaching of a label can be prevented and when direct printing is available, the man-hours required for attaching a label can be reduced, so that the operator can perform the operation effectively. Furthermore, label papers can be saved by use of direct printing, the working time can be reduced by the highly efficient operation, and the electricity consumption can be reduced, so that the system can contribute to protection of the earth""s resources.